[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Xen 4.0.1 "xc_map_foreign_batch: mmap failed: Cannot allocate memory"
>>> On 1/5/2011 at 07:37 AM, in message <alpine.DEB.2.00.1101051422360.2390@kaball-desktop>, Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> wrote: > On Thu, 16 Dec 2010, Keir Fraser wrote: >> On 16/12/2010 20:44, "Charles Arnold" <carnold@xxxxxxxxxx> wrote: >> >> >>> On 12/16/2010 at 01:33 PM, in message <C9302813.2966F%keir@xxxxxxx>, Keir >> > Fraser <keir@xxxxxxx> wrote: >> >> On 16/12/2010 19:23, "Charles Arnold" <carnold@xxxxxxxxxx> wrote: >> >> >> >>> The bug is that qemu-dm seems to make the assumption that it can mmap >> >>> from >> >>> dom0 all the memory with which the guest has been defined instead of the >> >>> memory >> >>> that is actually available on the host. >> >> >> >> 32-bit dom0? Hm, I thought the qemu mapcache was supposed to limit the >> >> total >> >> amount of guest memory mapped at one time, for a 32-bit qemu. For 64-bit >> >> qemu I wouldn't expect to find a limit as low as 3.25G. >> > >> > Sorry, I should have specified that it is a 64 bit dom0 / hypervisor. >> >> Okay, well I'm not sure what limit qemu-dm is hitting then. Mapping 3.25G of >> guest memory will only require a few megabytes of pagetables for the qemu >> process in dom0. Perhaps there is a ulimit or something set on the qemu >> process? >> >> If we can work out and detect this limit, perhaps 64-bit qemu-dm could have >> a mapping cache similar to 32-bit qemu-dm, limited to some fraction of the >> detected mapping limit. And/or, on mapping failure, we could reclaim >> resources by simply zapping the existing cached mappings. Seems there's a >> few options. I don't really maintain qemu-dm myself -- you might get some >> help from Ian Jackson, Stefano, or Anthony Perard if you need more advice. > > The mapcache size limit should be 64GB on a 64bit qemu-dm. > Any interesting error messages in the qemu logs? No, just the usual mmap error. See the attached logs. As a reminder, the following conditions exist to duplicate the problem. Host: x86_64 sles11sp1. Boot with dom0_mem=2048M, set (enable-dom0-ballooning no) in xend-config.sxp Hypervisor: x86_64 Xen 4.0.1 Guests: win2k3 (32bit) and win2k8r2 (64bit) The win2k8r2 guest uses robocopy to copy a 10 Gig file from the win2k3 guest. It copied about 23.2% before failing. Attachment:
qemu-dm-win-2k8r2.log Attachment:
qemu-dm-win2k3.log _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |